[sobarber]

OK, I figured out the NFS changes on Catalina. You have to do the edits to the plist from the Terminal started in the Recovery OS mode with the SIP disabled.

In the RecoveryOS, the boot volume will be mounted as "/Volumes/{Root Volume Name}" so the root volume is called  "Macintosh HD" then the boot volume would be mounted as "/Volumes/Macintosh HD"

The file to edit would be "/Volumes/Macintosh HD/System/Library/LaunchDaemons/com.apple.nfsd.plist"

And then you can reenable SIP before you reboot.